I am almost there, but am stuck on scanning (or adding muxes manually)
Using OSMC package app 4.0.7, have followed a 3.9 procedure by the Prof Yaffle; https://tvheadend.org/d/2590-step-by-step-tutorial-for-new-version-3-9?r=15363#message-15363
1. Configuration -> DVB Inputs -> Networks
Create a network of the appropriate type here. [_Mine is ATSC and I called it ATSC OTA_] You can have multiple networks of the same type, e.g. I have two DVB-T networks defined: one with HD muxes, one without, because one of my tuners doesn't support HD H.264.
2. Configuration -> DVB Inputs -> TV Adapters
[_My HDHomeRun Connect shows up, along with both tuners, and I follow the rest of this section_] Associate each of your tuners with the correct network. So, on mine, I have the HD DVB-T2 networks defined in Basic Settings -> Network on my HD tuners, but I have the SD network on the SD tuner and I have a DVB-S2 associated with my satellite tuners.
At this point, your tuners now know what networks to use: one network can appear on multiple tuners (many-to-one), and one tuner can have multiple networks.
3. Configuration -> DVB Inputs -> Muxes
This is where you'd manually add muxes or find the pre-defined ones you selected in step (1) - much like 3.4 at this point. [_Here's my problem point - nothing shows up, and an attempt to enter a manual mux on a strong local channel fails to scan_]
4. Configuration -> DVB Inputs -> Services
[_And this step won't work, naturally_] And this is where the services will appear as your tuners tune to the muxes based on the network you told them to look on.